Field of the Invention
The present invention relates to an element substrate and a liquid discharge head, and particularly to, for example, a full-line printhead to which a liquid discharge head incorporating an element substrate is applied to perform printing according to an inkjet method, and a printing apparatus for performing printing using the full-line printhead. More specifically, the present invention relates to a printhead mounting an element substrate on which a plurality of print elements and driving circuits for driving the respective print elements are provided, and a printing apparatus.
Description of the Related Art
As described in, for example, Japanese Patent Laid-Open No. 2009-160883, the electrothermal transducers (heaters) of a printhead mounted in a printing apparatus complying with the inkjet method and driving circuits of the heaters are formed on the same substrate using a semiconductor manufacturing process technique. As one configuration using the element substrate, there is proposed a printhead having a configuration in which an ink supply port is formed near the center of the element substrate, and a heater and an ink orifice corresponding to it oppose each other to sandwich the ink supply port.
As disclosed in Japanese Patent Laid-Open No. 2009-160883, in general, the heater and driver transistor are arranged adjacent to each other on the element substrate, a heater pitch and a driver transistor pitch are equal to each other, and one driver transistor is connected to one heater.
Japanese PCT National Publication No. 2010-505642 discloses an arrangement in a case where a plurality of chips are mounted on a printhead. In an element substrate having a shape of a parallelogram, since it is possible to arrange chips adjacent to each other by shifting them in a heater array direction, a head width can be shortened, as compared with a configuration in which a plurality of chips are arranged in a staggered pattern on a rectangular element substrate. Since, therefore, the heater distance with respect to a neighboring element substrate becomes short and ink orifices become closer to each other, it can be expected to improve the image quality in the connection portion of the element substrates. For this reason, various shapes other than a rectangle are proposed as the shape of the element substrate.
Along with a recent increase in print speed and recent improvement in image quality, the number of print elements integrated in a printhead is increasing. This imposes problems such as an increase in the area of an element substrate integrating circuits for driving the print elements, and optimization of the arrangement of heaters to mount a plurality of element substrates in a printhead in a case where the shape of each element substrate is a parallelogram, a trapezoid, or the like.
An increase in the area of an element substrate results in an increase in the size of a printhead, thereby influencing the size of a printing apparatus main body. This is a big problem conflicting with downsizing of the printing apparatus. Therefore, it is required to reduce the area of the element substrate.
If an element substrate has a shape such as a parallelogram, trapezoid, or uneven shape, the substrate end is inclined or has a concave shape. As for a conventional element and circuit layout, therefore, there is no region where a driver transistor corresponding to a heater in the vicinity of an end portion of the element substrate is arranged. Consequently, it is impossible to arrange a heater in the vicinity of the end portion of the element substrate. To implement a predetermined number of heaters, the substrate area increases, as compared with a rectangular element substrate, and the arrangement of driving circuits suitable for the substrate shape is thus required.